January 13, 2016Version 2016.1 now allows you to add
items to the database. Users can now manipulate the database
to the full extent. Read more...

January 23, 2015A third version of the manual was
uploaded. Contains new chapter about chemical background.Read more...

January 1, 2015After four beta-releases, the first
full-grown version was released.Read more...

What is CHEAQS?

CHEAQS Next is a computer program for calculating CHemical
Equilibria in AQuatic Systems. You supply
input data, the program calculates the chemical speciation for
you. CHEAQS Next is free but it is not cheap.

Features

You can calculate the concentration of complexes, but you
can also calculate:

redox equilibria;

complexation by natural organic matter (four different
models, three developed by Tipping and co-workers: Model V,
Model VI and Model VII; one developed by Cabaniss &
Shuman)

solids that are formed due to oversaturation (or just
calculate if they are oversaturated or not);

adsorption (surface complexation model).

pH: you can either specify a fixed pH or have the program
calculate the pH for you.

Input: you can edit input interactively (screenshot)
or read from an input file.

Output: You can view output on your screen (screenshot;
updated September 2016), save in an output file, or export to
an .CSV or .XML file (both types can be read by spreadsheet
programs like EXCEL 2002 and later).

Database

CHEAQS Next comes with a large database. Documentation is
available for each equilibrium reaction in the database so you
can always trace the source of an equilibrium reaction. In the
periodic table on the right, you can see (in green) which
elements are covered in CHEAQS Next' database. The database
contains: